The present invention relates to an aggregate module of a combustion engine, with the module comprising as the first aggregate a unit for separating contaminants from the lubricating oil of the combustion engine, with the unit being provided with a filter element, a free-jet centrifuge drivable by lubricating oil flowing through it, at least one inlet duct for lubricating oil to be purified, one outlet duct for lubricating oil that has flown through the filter element, and one return duct for lubricating oil that has flown through the centrifuge, and with the centrifuge placed above the filter element in a common housing.
A unit for separating contaminants from the lubricating oil of a combustion engine, as described above, is known from DE 43 06 431 C1.
As is known, it is practice in the automotive industry to comprise the aggregates of a combustion engine to aggregate modules. These aggregate modules can then be prefabricated and preassembled to the largest extent possible and are then, in a final step, connected to other parts of the combustion engine, for example to the engine block. A concrete example of such an aggregate module is a combination of oil filter and fuel filter, which are forming the first and second aggregates. At their outer circumference, the housing of these two filters possess connection elements protruding to the outside, where the two housings are connected to one another, preferably by means of several screws. The central axes of the two housings are, in substance, aligned in parallel to one another, with each housing possessing a cover at its upper side, that can be removed for maintenance purposes. This known aggregate module is used on Diesel engines in trucks and busses.
In practice, increasingly strict exhaust-emission regulations cause the problem of the lubricating oil of combustion engines, in particular Diesel engines, being increasingly contaminated with fine particles, in particular soot. To remove these particles affecting lubrication adversely from the lubricating oil, the lubricating oil requires improved filtration. Theoretically, this can be achieved by using a filter element with a lower porosity, i.e., with a higher filter fineness. However, the disadvantage of such a filter element is, on the one hand that its flow resistance is higher and, on the other hand, its working life is shorter than the flow resistance and working life of the filter elements used presently. These two factors adversely affect the operation of the combustion engine and are, thus, unwanted. In practice, elimination of these factors by enlarging the filter element is excluded because of the missing free space. A second possibility of improving filtration of the lubricating oil is to combine the filter element with a centrifuge, this combination as such being known from the state-of-the-art. With a given free space, integration of the centrifuge can be achieved by reducing the height of the filter element and placing the centrifuge in the same housing above the filter element. This, however, raises the problem of an additional return duct from the centrifuge having to be created for discharging the lubricating oil that has flowed through the centrifuge. This return duct must possess a cross-section of appropriate size, so that the lubricating oil, pressureless after it has flowed through the centrifuge, can flow of quickly enough under the influence of gravity, usually into the oil pan of the combustion engine. With a given free space that cannot be increased, such a return duct can only be integrated in the unit for purifying the lubricating oil at the expense of the size of the filter element, this having the disadvantage, however, that the filter surface of the filter element is reduced to an excessive extent.